# Database

> Designs normalized database schemas, creates indexes, writes efficient queries, and manages transactions and data integrity.

- Skill: `neuralblitz/database` (Agent Skill)
- Install (CLI): `npx skillmds@latest add neuralblitz/database`
- Raw SKILL.md: https://api.skillmd.com/api/skills/neuralblitz/database/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Data & Analytics, AI & ML, SQL & Databases
- Tags: Database Design, Indexing, Query Optimization, Schema Design, Sql, Transactions
- License: MIT
- Author: NeuralBlitz (https://skillmd.com/u/neuralblitz)
- Updated: 2026-08-22
- Page: https://skillmd.com/skills/neuralblitz/database

---

## What I do
- Design database schemas
- Normalize data structures
- Create indexes for performance
- Write efficient queries
- Handle transactions
- Implement data integrity
- Optimize queries
- Manage database connections

## When to use me
When designing databases or writing queries.

## Schema Design
```sql
-- Normalized schema
CREATE TABLE users (
    id BIGINT PRIMARY KEY,
    email VARCHAR(255) NOT NULL UNIQUE,
    created_at TIMESTAMP DEFAULT NOW()
);

CREATE TABLE orders (
    id BIGINT PRIMARY KEY,
    user_id BIGINT REFERENCES users(id),
    total DECIMAL(10, 2) NOT NULL,
    status VARCHAR(50) DEFAULT 'pending',
    created_at TIMESTAMP DEFAULT NOW()
);

-- Index for performance
CREATE INDEX idx_orders_user ON orders(user_id);
CREATE INDEX idx_orders_status ON orders(status) WHERE status = 'pending';
```

## Query Optimization
```sql
-- Use EXPLAIN ANALYZE
EXPLAIN ANALYZE
SELECT * FROM orders
WHERE user_id = 123
ORDER BY created_at DESC
LIMIT 20;

-- Avoid SELECT *
-- Use covering indexes
-- Pagination with LIMIT/OFFSET
-- Batch operations
```